I have created am open api 3.0 version specification. Then I used the tool to generate the spring code. When I started the API service, it created the specification with version Swagger 2.0. The code generated uses swagger jar which doesn't support openapi 3.0 specification.
openapi-generator version : 3.1.2
OpenAPI declaration file content or url
https://app.swaggerhub.com/apis/arpit9mittal/Test/2.0.0-oas3#/
Command line used for generation
openapi-generator generate -i arpit9mittal_Test_2.0.0-oas3_swagger.json -g spring -o test